As tvpierce says, you are living on borrowed time. Get this taken care of ASAP or you'll be faced with drilling out the cylinder yourself or paying a dealer big bucks to do it. Take your car ID and proof of ownership to MB and get a like keyed cylinder in about a week (about $90 two years ago). Or you can immediately get a generic cylinder from MB but then you'll have two different keys for the car. Replacement is straightforward. Check the archives. You can start the car with just a screwdriver after the cylinder has been removed (but so can anyone else!)

As danieldono mentioned, the cast aluminum cylinder housing is weak and does break. It is weak from all the cut out slots that the brass lock pins fit into.


glenmore
1991 300CE
1990 LS400